Abstract:

The efficiencies of chlorine dioxide delignification and oxygen delignification and corresponding bleaching sequences were investigated comparatively.The results indicated that the effect of ClO₂ delignification (D₀) on the modification of residual lignin was better than that of O₂ delignification (O).Under the conditions of lower than and near to the removal rate of O₂ delignification，the bleachability of D₀ stage pulp was superior to that of O stage pulp.With the same removal percentage of delignification，the final brightness of bleached pulp by D₀A/QP sequence and D₀EP sequence were 11.2 and 10.3 points higher than the ones bleached by OA/QP sequence respectively，where A/Q stand for the acid chelating stage，E for alkaline extraction and P for hydrogen peroxide bleaching stage respectively.The COD_Cr loads of the D₀ stage filtrate and corresponding mixed effluents by three stages of D₀A/QP sequence were lower than those of O stage filtrate and corresponding mixed effluents by three stages of OA/QP sequence.Additionally，the characteristic absorption of aromatic ring of lignin was found in the UV spectroscopy of D₀ filtrates and O filtrates.FT-IR spectroscopy analysis of unbleached and bleached pulps suggested that the amounts of hydroxyl and carbonyl increased in the D₀ pulps and O pulps.With the subsequent bleaching stages，main chromophores such as carbonyl gradually decreased and a high brightness of pulp was obtained.The SEM analysis of fiber morphology revealed that the destruction and damage of the surface of fibers in D₀ stage and corresponding D₀A/QP sequence were less than those of O stage and corresponding OA/QP sequence.

Key words:

二氧化氯脱木素, 氧脱木素, 麦草浆, 漂白流程

摘要：

对麦草浆二氧化氯与氧气脱木素效率及相应的漂白流程进行了对比研究。结果表明，ClO₂脱木素(D₀)对木素的修饰和改性效果好于氧脱木素(O)，在脱木素率低于及接近氧脱木素率的条件下，D₀浆的可漂性均大于O浆。在D₀段和O段脱木素率相同的条件下，采用D₀A/QP、D₀EP漂白流程漂后纸浆白度分别比OA/QP漂白流程高11.2和10.3个百分点。D₀段废液和相应D₀A/QP漂白流程三段混合废水的COD_Cr负荷均比O段和OA/QP漂白流程混合废水的COD_Cr负荷轻。D₀段和O段废液的紫外光谱都呈现出木素苯环的特征吸收。纸浆的FT-IR谱图分析表明，D₀浆和O浆中的羟基和羰基数量增多，随着漂白的进行，羰基等主要发色基团逐渐消除，纸浆白度得到提高。纸浆纤维形态的SEM分析显示，D₀段和相应的D₀A/QP漂白流程对纤维表面的破坏和损伤较O段和相应的OA/QP漂白流程轻。

关键词:

二氧化氯脱木素, 氧脱木素, 麦草浆, 漂白流程